The condition of ailing veteran Marxist Harkishan Singh Surjeet is ‘very serious’ and his chances of survival are ‘very less’, doctors treating him said as Prime Minister Manmohan Singh visited the hospital here where the 92-year-old-leader is admitted.The overall picture considering his age, his coming back (from the coma) is very difficult," Dr Purushottam Lal, head of the Cardiology Department of the Metro Hospital, said."Survival is very very uncertain, chances are very less. It is a matter of a few days," Lal said. Surjeet was admitted to the hospital with an acute respiratory problem on May 6.Earlier, the Prime Minister drove to the hospital and enquired about Surjeet's condition from the doctors attending on him."We had been in touch with the PMO earlier also and they had been monitoring the situation. He (the Prime Minister) knew about his condition, and today, he again enquired about his condition," Lal said.Singh, who was with the CPM leader for about 10 minutes, appreciated the efforts being put in by the doctors.The doctors said they tried to revive Surjeet but he slipped into comma on Friday after responding to an extent to the treatment.Due to his failing health, Surjeet was, for the first time, not included in the CPM Politburo at the party's 19th Congress in April this year. He was instead designated as Special Invitee to the Central Committee.